Archive for August, 2012


        For those who may have forgotten, Alice(The Wonderland one) travels through a portal into a parallel Universe. Although talking about the movie would be very interesting. I would, however, like to focus on this “portal” that Alice travels through. To be more specific, the “portal” is a theoretical concept in physics known as a “Wormhole”.(Yes, it’s real!)

        There are two different concepts that require a bit of clarification here- Time-Travel(as the name suggests) and Space-Travel(that is travelling through large distances in a relatively short time). In this post, I’ll focus more on space travel. Einstein’s Special Theory of Relativity(there’s no need to know more than the name here) seemed to have imposed a serious constraint on our ability to space travel. And, since we cannot travel faster than light, that would imply 8 years if we tried to travel near Proxima Centauri(the other star that is closest to us). And 80 years to the galactic center. I seriously doubt we would find any volunteers for this.

        That should, however, not dampen our enthusiasm about Space-Travel. A small thought experiment is worthwhile here(the same Einstein used to do). Alright, so if I asked you what is the smallest distance between two points on a surface, you would most probably answer: “that’s pretty simple, it’s a straight line between these two points!” At this point, you would probably want to laugh at my stupidity. But, I would then humbly answer- ‘Nope’. You see, this straight line is the same restraint that the limit of light imposes on us(and prevents us from finding any volunteers). The answer is to warp the surface. You fold the surface(like a paper) so that the two points touch or are aligned to each other and Ta-Dah!, away goes all the limits that once existed. Distance is annihilated. This also implies the possibility of space-travel.

        This warping of space is real-physics(we’ve all heard about curved spacetime!- that was what made Einstein so famous).We can actually observe this when light ‘bends’ a bit as it  travels close to the sun-‘Gravitational Lensing‘(just another name) caused by the sun’s mass.(shown on the picture). Remember how the rocket from Apollo 13 was rescued by going round the moon.  Same stuff.

        What we just need now is to ovecome the energy constraint of several billion billion(and many more billions) Terajoules. No hard stuff!

        Space-Travel, Time-Travel and Wormholes sound pretty fascinating when related as such but all these are still pretty much virgin territory. You wouldn’t find many researchers working on Time-Travelling because of all the ethical issues that are portrayed in Steven Spielberg’sBack To The Future”(that’s what the “spacetime-continuum” dilemma that “Doc” continuously rambled about in the movie). But science has “a way” of doing things and who knows what may happen? Who could have guessed there would be people reading a blog about space-travel written by a deranged blogger who thinks “science can be fun”.

Almost forgot- What did Alice tell Einstein? I haven’t got the faintest idea!!(I just thought it would make a Great Title!) 

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Mom: Alice, can you go to Pluto and bring me those delicious Plutonian-flavored ice cubes.

Alice: Not again, Mom! I went there just yesterday.Besides, there are still some ice-cream left in our fridge on Mars.

Mom: Alice, this is for your Grandma. I want you to go to 1960 and give it to her.

Alice: Mom, Time-Travel makes me sick!

(Mom frowns)

Alice: Okay, okay, I’m going!

//Short Story By Vasish//

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For anyone interested in deeper “Travelling”, I suggest reading Stephen Hawking‘s lecture.

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We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special.” Stephen Hawking.

 

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    This post is (partly) an answer to the puzzle that I posted here (Why’s the sky dark at night?).                                                                                                            Did I say partly? The reason is that this “paradox”(The Olber’s Paradox as it is [in]famously known) has yet to be completely answered.

 According to Henrich Olber, the   sky should look something like the image that I found on Wikipedia(and found particularly apt for this post). But that’s not the case, right? Several explanations have been proposed for this somewhat ‘strangeness.’

Theory 1: Dust present between the stars and the galaxies veils the light that we should be seeing.

What’s wrong with it? The dust from the stars would eventually heat up and start radiating the light.(that’s one theory that eats the “dust”)

Add-fact: Even if all the matter in the Universe were converted to Energy(the famous e=mc^2), given the immensity of the Uni., the   energy would be just enough to raise the temperature of the Uni. to 20 kelvin(that’s about -253 deg.Celcius- not very much, huh!)

Theory 2: Let’s bring some “Big-Bang” to this paradox. Galaxies are dispersing, always running(or flying) away from each other(that’s the Big-Bang Theory!). So, a phenomenon known as the redshift occurs. As a sidenote, redshift is the same phenomenon that occurs  when the pitch of a siren increases when it approaches you and lessens as it moves away(here’s an audio). The main difference here is that it’s light. As another sidenote, light consists of a spectrum, there is the visible region(made up of the colors), there is the microwave region(the name says it all), the radio region and a host of other. The difference is the frequency with which vibration occurs. Returning to our paradox now.

So, according to the theory, the visible part gets shifted to the invisible infrared part(are you still with me?) and that’s why we do not see the light(literally).

Something’s wrong, again!! : The problem with this explanation is that if there is a shift in the visible region, then, there should also a shift from the other Ultraviolet region to the Visible one and we are (again) at square one.

What, another theory(3)?: Yep. This one’s a little tricky. The dark sky is due to the large distance light has to travel to reach us. It is, more scientifically speaking, attenuated as it reaches us.

Triple Trouble:Let’s take a concentric layer on which stars are uniformly spaced. If we decrease the distance from the centre, the ellipse formed will be shorter and thus, there will be lesser stars on this one. Now, we would be right if we said that the light from the distant stars gets attenuated by a certain factor f when it reaches the other stars. However there is a factor f  more stars on the larger ellipse. The net effect is a cancellation!

What’s Generally Accepted: Today’s most apt explanation is “The Universe NOT being infinitely old although infinitely large”. Light has a finite velocity(~300000 kpsecond) and light from the distant galaxies takes some time to reach us. For e.g light from the sun takes about 8 minutes to reach the Earth, so we’re seeing the sun as it was 8 min. ago. As it stands, our Universe is approx. 13 billion years old. So, we cannot see light beyond that! Galaxies, on the other hand, do not live infinitely, their emitted light dim. These two conditions prevent a fully blazing night sky to be seen.

The Trouble: Just Jokin’, I leave it to you to find it and possibly gain International fame!

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“He who is fixed to a star does not change his mind.” -Leonardo da Vinci

                        Whenever he is alone at night, Henrich likes to watch the beautiful stars in the sky. It so happened that, one day, as Henrich was sitting at his usual spot, a seemingly innocuous thought flashes across his mind- “why is the sky dark at night?”- he asks. Being rather proficient with Science, Henrich is able to determine that if the Universe is uniformly filled with stars, the whole of the night sky should be blazing with lights from these stars, but that isn’t the case. “Why?”, he asks. Why, indeed?

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The answer to this question is perhaps one of the most famous paradoxes known in science!

You cannot teach a man anything; you can only help him discover it in himself.” -Galileo

Here’s the answer!

 
 

      Trying to combine quantum physics and blogging may sound very strange (well, it is!)  and is possibly the fruit of a deranged mind(well, that also is!). This a simply a post for bloggers (and future bloggers) out there.Ever wondered what bloggers will be like in, say, 50 or so years. What will be the most important tool they would be using (classically called the computer).The title’s the answer- they could be Quantum Bloggers(…or maybe not!)

     So, what’s all the fuss about being a Quantum Blogger? Or, more importantly what will be the tool that our future GrandBloggers (that means the grandchildren of bloggers) would be using? The answer may be Quantum Computers (Of course, that doesn’t mean that all our GrandBloggers will have to be Quantum Physicists!).

      The salient thing here is the Quantum Computer. Allow me to add a bit of historical perspective. Long ago (that’s in the 50s), computers were fat (even that is euphemistically speaking). With the advent of better tech, computer parts shrunk (and with the advent of more tech, parts shrunk even more). So came a little dilemma (a theoretical one) posed by the thinking people- we cannot possibly shrink these parts infinitely, there’s got to be a limit to it, right? (we have yet to reach that limit though). Fact is, there is (classically speaking). So came our very dear Quantum Computers (atleast in concept).

     Very strangely, though, the concept of quantum computing dates back to the 1960s. It is the brainchild of Richard Feynman(he crops up everytime, doesn’t he?). Now, before you start accusing our scientists of indolence and ‘not doing anything’, allow me to clarify, it is the strange Quantum World that we’re talking about here and by the time I explain, you’ll see how strange everything is!

      The Quantum computer is a hybrid of Quantum Physics and Computing. And when these two combine..These computers will have the computing efficiency of many classical computers put together(exponentially) and will have the ability to toy with as many figures as there are atoms in the Universe (phew!) instantly. They operate on Qubit(that’s quantum bits). While we are familiar with the 1s and 0s of classical computers, quantum computers use both at the same time(that’s the strange world of quantum physics and superposition).

      Now, let’s address the question of whether our GrandBloggers would be Quantum Bloggers? The answer(quite unfortunately or… not) is a NO! At present, the most that Quantum Computers could do is like looking up a name [very fast] in a phonebook or doing prime factorisation. That does not make them very useful (and that’s why we do not see them today on our tables)

      But let’s not just be negative about this. There might be a generation of Quantum Bloggers one day. For now, let’s just enjoy a good old Beatles song on our Macs. Who knows when these might become obsolete? Cheers to that!

                         “I, a universe of atoms, an atom in the universe.” Richard P. Feynman
 
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As an endnote, for those interested in the strange world of Quantum Computing, see:
http://arstechnica.com/science/2010/01/a-tale-of-two-qubits-how-quantum-computers-work/ or
http://computer.howstuffworks.com/quantum-computer.htm
 
 

“Alienated”

An Alien Poll:

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“Where are they, anyway?”Enrico Fermi